The use of cyanoacrylates and methacrylates to apply artificial nails to nail tips is not new. Various method have been developed to try to make the application of an artificial nail tip to a finger nail safer, easier, quicker and more economical and effective. They have been met with varying degrees of success, but still each suffer from differing types of problems or difficulties.
Some examples are disclosed in U.S. Pat. No. 5,824,180 to Mikuni, et al. The Mikuni patent discloses the prior art method of: (i) bonding an artificial nail tip to a finger nail with an adhesive; (ii) then applying a polymerizing resin to fill in the recessed part of the junction between the artificial nail tip and finger nail; (iii) then applying a polymerization accelerator; (iv) filing the resulting polymerized surface; and (v) coating the resulting nail surface with a lacquer or resin. This method requires the user to engage in the substantial, time-consuming effort of filing the polymerized resin surface. In addition, the Mikuni reference teaches that use of polymerization accelerators involves use of a solvent, which generates an odor that is unpleasant, and creates a troublesome working environment.
The Mikuni patent is directed toward trying to overcome these types of difficulties by use of photocurable adhesive. Photocurable adhesives have not proven satisfactory for a variety of reasons such as expense, lengthy curing times, and difficulty of controlling the timing of the curing process once the photocurable adhesive is exposed to light.
Other prior art methods are disclosed in U.S. Pat. No. 4,626,428 to Weisberg, et al. For example, the Weisberg, et al. patent describes the following prior art nail sculpting process: (i) cleaning, roughening and treating a finger nail with bromide; (ii) coating the nail with an adhesive such as cyanoacrylate ester, or a primer container methacrylic acid that binds the acrylic to the nail; (iii) wetting a brush with liquid methacrylate esters and a promoter, such as toluidine, to induce the decomposition of benzoyl peroxide applied in the next step; (iv) dipping the brush in powered methacrylate containing benzoyl peroxide to act as a polymerization catalyst, causing the methacrylate esters and powder to polymerize sufficiently to provide a dough-like substance; (v) brushing the dough on the nail; and (vi) after the dough has cured and hardened in place on the finger nail, sculpting the artificial nail surface on the surface of the hardened dough.
The Weisberg, et al. patent explains that this sculpting method is very difficult to perform. This sculpting method requires substantial dexterity, time, and experience to properly apply and sculpt the polymer dough, including substantial filing of the dough after it has cured. The sculpting method also ruins the brush since a substantial quantity of the dough often hardens in place on the brush.
The Weisberg, et al. patent describes other variants of the nail sculpting method in which the nail is first wetted and then dipped into a powder, rather than applying a dough, and then covered with other seal and fill coats. The Weisberg patent notes that the prior art methods do not induce sufficient cross-linking of the monomers in the various components, so the resulting nail is not sufficiently strong and durable.
The method of the Weisberg, et al. patent seeks to solve these problems by first applying a solvent to the brush prior to exposure of the brush to the liquid. The solvent helps prevent polymerization and bonding to the brush. In addition, the Weisberg method teaches dipping of the wetted nail in a resin powder of polymethacrylate esters and benzoyl peroxide, which is then again coated with liquid methacrylate ester monomers for curing and cross-linking of the liquids and powder in air. This prior art method, however, requires use of solvents of the type that prevent polymerization, and as noted by the Mikuni patent, these types of solvents present significant working environment issues.
U.S. Pat. No. 4,687,827 to Russo also discloses a method of applying nail tips by use of polymerization accelerators to achieve shortened curing time. The Russo patent also discloses extension of shelf life of cyanoacrylate adhesive, prior to application of the adhesive, by addition of polymerization inhibitors such as hydroquinone. The Russo patent also suggests inclusion of silica to build up the nail surface. Like the Weisberg patent, however, the Russo patent does so in the context of teaching use of pre-wetting solvent to keep the liquid adhesive cyanoacrylates from curing too soon.
U.S. Pat. No. 4,844,102 to Repensek discloses use of a dryer sprayed on cyanoacrylate to encourage faster polymerization during application of an artificial finger nail tip. The Repensek method, however, also involves use of a polymer solvent (and the attendant problems and issues noted above). In the Repensek method, the solvent is applied after application of the applied monomers and polymers in order to dissolve, spread, and shape them and, by the endothermic evaporation of the solvent, reduce the amount of heat otherwise imparted to the finger nail by the exothermic reaction of the polymerizing components.
U.S. Pat. No. 5,770,184 to Keller teaches the application of a nail tip by applying one or (optionally when used to apply a prefabricated nail) two coats of cyanoacrylate adhesive followed by immediate application of a nail tip. The Keller patent teaches that the user should then wait for the cyanoacrylate adhesive to dry and secure the nail tip to the finger nail, and then add additional coats of cyanoacrylate followed by spraying the cyanoacrylate coats with a mixture of pink acrylic powder and sodium bicarbonate to accelerate polymerization. The Keller patent also suggests use of benzoyl peroxide in the powder, to accelerate polymerization, and the use of opaquing agents such as silicon dioxide. The Keller method requires a substantial amount of time waiting for the first and, if applied, second coat of cyanoacrylate adhesive to dry under the applied vinyl nail tip. The applicant also believes that the nail resulting from the Keller patent is not as strong as is desirable.